Switch md button to open to side by default

Fixes #21511
Fixes #23922

Changes the default markdown toolbar item to open the preview to the side of the current file as requested by #21511

Also updates the single file preview icon slightly to better differentiate it from the diff icon

extensions/markdown/media/Preview.svg

-<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0.414 0 16 16" enable-background="new 0.414 0 16 16"><path fill="#F6F6F6" d="M12.363 4c-.252-2.244-2.139-4-4.449-4-2.481 0-4.5 2.019-4.5 4.5 0 .6.12 1.188.35 1.735l-3.764 3.765 2.414 2.414 3-2.999v6.585h11v-12h-4.051z"/><rect x="12.414" y="10" fill="#424242" width="1" height="3"/><rect x="10.414" y="11" fill="#424242" width="1" height="2"/><rect x="8.414" y="12" fill="#424242" width="1" height="1"/><rect x="8.414" y="9" fill="#424242" width="2" height="1"/><path fill="#424242" d="M12.363 5c-.039.347-.112.681-.226 1h2.276v8h-7v-5.05c-.342-.039-.676-.112-1-.228v6.278h9v-10h-3.05z"/><path fill="#424242" d="M10.708 8h1.706v-1h-.762c-.257.384-.585.712-.944 1z"/><path fill="#424242" d="M11.414 4.5c0-1.933-1.567-3.5-3.5-3.5s-3.5 1.567-3.5 3.5c0 .711.215 1.369.579 1.922l-3.579 3.578 1 1 3.579-3.578c.552.363 1.211.578 1.921.578 1.933 0 3.5-1.567 3.5-3.5zm-5.999 0c0-1.381 1.119-2.5 2.5-2.5s2.5 1.119 2.5 2.5-1.12 2.5-2.5 2.5-2.5-1.119-2.5-2.5z"/><path fill="#F0EFF1" d="M12.138 6c-.126.354-.279.693-.485 1h.762v1h-1.706c-.771.616-1.734 1-2.795 1-.169 0-.333-.031-.5-.05v5.05h7v-8h-2.276zm-3.724 3h2v1h-2v-1zm1 4h-1v-1h1v1zm2 0h-1v-2h1v2zm2 0h-1v-3h1v3z"/><circle fill="#F0EFF1" cx="7.914" cy="4.5" r="2.5"/></svg>
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+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"><style>.st0{fill:#f6f6f6}.st1{fill:none}.st2{fill:#424242}.st3{fill:#f0eff1}</style><path class="st0" d="M11.949 4C11.697 1.756 9.811 0 7.5 0A4.505 4.505 0 0 0 3 4.5c0 .6.12 1.188.35 1.735L0 9.586v.828l2 2 3-2.999V16h11V4h-4.051z" id="outline" style="display: none;"/><g id="icon_x5F_bg"><circle class="st1" cx="7.5" cy="4.5" r="2.5"/><path class="st2" d="M12 10h1v3h-1zM10 11h1v2h-1zM8 12h1v1H8zM8 9h2v1H8z"/><path class="st2" d="M11.949 5a4.431 4.431 0 0 1-.226 1H14v8H7V8.95a4.447 4.447 0 0 1-1-.227V15h9V5h-3.051z"/><path class="st2" d="M10.294 8H12V7h-.762a4.527 4.527 0 0 1-.944 1zM11 4.5a3.5 3.5 0 1 0-7 0c0 .711.215 1.369.579 1.922L1 10l1 1 3.579-3.578A3.485 3.485 0 0 0 7.5 8 3.5 3.5 0 0 0 11 4.5zm-6 0a2.5 2.5 0 1 1 5 0 2.5 2.5 0 0 1-5 0z"/></g><g id="icon_x5F_fg"><path class="st1" d="M10 11h1v2h-1zM8 12h1v1H8zM8 9h2v1H8zM12 10h1v3h-1z"/><path class="st3" d="M11.724 6a4.469 4.469 0 0 1-.485 1H12v1h-1.706c-.771.616-1.733 1-2.794 1-.169 0-.333-.031-.5-.05V14h7V6h-2.276zM8 9h2v1H8V9zm1 4H8v-1h1v1zm2 0h-1v-2h1v2zm2 0h-1v-3h1v3z"/><circle class="st3" cx="7.5" cy="4.5" r="2.5"/></g></svg>
\ No newline at end of file

extensions/markdown/media/Preview_inverse.svg

-<svg xmlns="http://www.w3.org/2000/svg" width="16" height="16" viewBox="0.414 0 16 16" enable-background="new 0.414 0 16 16"><path fill="#252626" d="M12.363 4c-.252-2.244-2.139-4-4.449-4-2.481 0-4.5 2.019-4.5 4.5 0 .6.12 1.188.35 1.735l-3.764 3.765 2.414 2.414 3-2.999v6.585h11v-12h-4.051z"/><rect x="12.414" y="10" fill="#C5C5C5" width="1" height="3"/><rect x="10.414" y="11" fill="#C5C5C5" width="1" height="2"/><rect x="8.414" y="12" fill="#C5C5C5" width="1" height="1"/><rect x="8.414" y="9" fill="#C5C5C5" width="2" height="1"/><path fill="#C5C5C5" d="M12.363 5c-.039.347-.112.681-.226 1h2.276v8h-7v-5.05c-.342-.039-.676-.112-1-.228v6.278h9v-10h-3.05z"/><path fill="#C5C5C5" d="M10.708 8h1.706v-1h-.762c-.257.384-.585.712-.944 1z"/><path fill="#C5C5C5" d="M11.414 4.5c0-1.933-1.567-3.5-3.5-3.5s-3.5 1.567-3.5 3.5c0 .711.215 1.369.579 1.922l-3.579 3.578 1 1 3.579-3.578c.552.363 1.211.578 1.921.578 1.933 0 3.5-1.567 3.5-3.5zm-5.999 0c0-1.381 1.119-2.5 2.5-2.5s2.5 1.119 2.5 2.5-1.12 2.5-2.5 2.5-2.5-1.119-2.5-2.5z"/><path fill="#2B282E" d="M12.138 6c-.126.354-.279.693-.485 1h.762v1h-1.706c-.771.616-1.734 1-2.795 1-.169 0-.333-.031-.5-.05v5.05h7v-8h-2.276zm-3.724 3h2v1h-2v-1zm1 4h-1v-1h1v1zm2 0h-1v-2h1v2zm2 0h-1v-3h1v3z"/><circle fill="#2B282E" cx="7.914" cy="4.5" r="2.5"/></svg>
\ No newline at end of file
+<svg xmlns="http://www.w3.org/2000/svg" viewBox="0 0 16 16"><style>.st0{fill:#2d2d30}.st1{fill:none}.st2{fill:#c5c5c5}.st3{fill:#2b282e}</style><path class="st0" d="M11.949 4C11.697 1.756 9.811 0 7.5 0A4.505 4.505 0 0 0 3 4.5c0 .6.12 1.188.35 1.735L0 9.586v.828l2 2 3-2.999V16h11V4h-4.051z" id="outline" style="display: none;"/><g id="icon_x5F_bg"><circle class="st1" cx="7.5" cy="4.5" r="2.5"/><path class="st2" d="M12 10h1v3h-1zM10 11h1v2h-1zM8 12h1v1H8zM8 9h2v1H8z"/><path class="st2" d="M11.949 5a4.431 4.431 0 0 1-.226 1H14v8H7V8.95a4.447 4.447 0 0 1-1-.227V15h9V5h-3.051z"/><path class="st2" d="M10.294 8H12V7h-.762a4.527 4.527 0 0 1-.944 1zM11 4.5a3.5 3.5 0 1 0-7 0c0 .711.215 1.369.579 1.922L1 10l1 1 3.579-3.578A3.485 3.485 0 0 0 7.5 8 3.5 3.5 0 0 0 11 4.5zm-6 0a2.5 2.5 0 1 1 5 0 2.5 2.5 0 0 1-5 0z"/></g><g id="icon_x5F_fg"><path class="st1" d="M10 11h1v2h-1zM8 12h1v1H8zM8 9h2v1H8zM12 10h1v3h-1z"/><path class="st3" d="M11.724 6a4.469 4.469 0 0 1-.485 1H12v1h-1.706c-.771.616-1.733 1-2.794 1-.169 0-.333-.031-.5-.05V14h7V6h-2.276zM8 9h2v1H8V9zm1 4H8v-1h1v1zm2 0h-1v-2h1v2zm2 0h-1v-3h1v3z"/><circle class="st3" cx="7.5" cy="4.5" r="2.5"/></g></svg>
\ No newline at end of file

extensions/markdown/package.json

@@ -80,8 +80,8 @@
 			"editor/title": [
 				{
 					"when": "editorLangId == markdown",
-					"command": "markdown.showPreview",
-					"alt": "markdown.showPreviewToSide",
+					"command": "markdown.showPreviewToSide",
+					"alt": "markdown.showPreview",
 					"group": "navigation"
 				},
 				{